When excising tumors it is critical to remove the whole of diseased tissue, but cancer margins can be indistinguishable from healthy tissue to the human eye. Researchers at Washington University in St. Louis have created a heads-up display that utilizes indocyanine green (ICG) dye solution to allow surgeons to see exactly where the cancer is.
Indocyanine green is a fluorescent dye that glows when illuminated with specific light frequencies. In medicine it’s highly useful as a marker because it binds to proteins in blood plasma and indicates where vasculature lies and how blood is moving through it. Since tumors are more vascularized than healthy tissue, ICG injected into vessels leading to the tumor make it light up when viewed with the new goggle system. The goggles project light at the dye’s absorption frequency and detect the light it emits. The glow is superimposed on the live picture of the scene in front of the glasses, providing a live view of the tumor among the unpainted healthy tissue.